The present invention pertains to valves and particularly to electrostatically actuated valves. More particularly, the invention pertains to electrostatically actuated valves for modulation.
A patent application that may relate to the present invention is U.S. patent application Ser. No. 10/174,851, filed Jun. 19, 2002, which is herein incorporated by reference. Patents that may relate to the present invention include U.S. Pat. Nos. 6,288,472; 6,179,586; 6,106,245; 5,901,939; 5,836,750; and 5,822,170; all of which are herein incorporated by reference. This application may be related to a patent application having Ser. No. 11/025,758, entitled “Electrostatically Actuated Gas Valve” by Bonne et al., and being filed approximately concurrently, and a patent application having Ser. No. 11/018,799, entitled “Media Isolated Electrostatically Actuated Valve” by Cabuz et al., all of which are incorporated herein by reference.
Electrostatic actuators which are voltage driven may be controlled relative to only one-third of the total displacement when a pull-in (viz., snapping) effect occurs. The voltage span for this control may have many times a small value making the valve control a difficult task. In other words, electrostatic actuators may be voltage driven for a limited displacement; however, a pull-in effect may occur after that displacement. There may be many techniques to delay or avoid this phenomenon that makes many electrostatic actuators inappropriate for many applications.